201042150 六、發明說明： 【發明所屬之技術領域】 本發明係有關於一種由灰鑄鐵或球墨鑄鐵 cast iron )所製成之真空栗外殻。 【先前技術】 真空泵包含複數個泵啷元件，其被配置在 所構成之泵唧室中。真空泵主要地被構造成螺 氏泵（Roots)、迴轉式真空泵、及爪式泵。爲了 〇 有必要在諸栗元件與栗啷室之內壁間形成一 的間隙。爲此目的，有必要使真空泵運轉在一 之操作溫度下，以避免由於泵外殼與諸泵元件 脹所可能導致在該間隙上之改變。 提供具有冷卻肋件之真空泵並藉由使用 卻此泵外殻之作法係屬習知的。然而，在這 中’外殻之均勻且經良好定向的冷卻將通常可 特殊措施而達成，諸如藉由安裝一具有經良好 ^ 導引的外箱，或藉由使用一外部風機系統（由 一者或一分離之驅動單元所驅動）。該空氣流 另外缺點在於：低冷卻強度及難以不受外部影 諸如氣流或不宜地覆蓋住泵之物體。 另外，藉助於水或冷卻液體來進行真空泵 的作法係爲習知。水冷卻需要特殊之結構措 ® ’水必須被盡可能接近地導引至諸待冷卻部 獲得最高之冷卻效果。另一方面，水對於大部 (spheroidal 一由一外殼 旋式泵、魯 產生真空， 盡可能最小 盡可能均一 之不同熱膨 一氣流來冷 些背景技藝 僅藉由一些 定向之空氣 諸泵軸中之 動式冷卻之 響或干擾， 外殼之冷卻 施。在一方 分，以便可 分材料之腐 201042150 蝕效果將使得無法在無採取特殊保護措施之下使用水。爲 了避免腐蝕，可用不會腐蝕之材料，諸如不鏡鋼或特定之 鋁合金。然而’此類材料昂貴且不符合真空泵外殼之其他 先決條件，諸如抗高溫性，尤其是大於250°C者。另外， 亦可在與水相接觸的諸表面上塗漆。要確實地將多個位於 外殼內側處之相對應通道塗以油漆是非常錯綜複雜的。此 塗漆程序必須藉由浸沒槽浴或藉由用於攪動漆液之轉動 及翻攪動作而予進行。另外，電鍍表面處理法（例如鍍鋅 或鍍鎳）乃習知用於鑄鋼及灰鑄鐵之情形，而硬質陽極處 理則習知用於鋁之情形。然而，這些方法也都是非常複 雜。此外。另一習知方法是使用自耗電極，但其亦爲一複 雜之方法。且在內部冷卻通道情形中無法可靠地防止腐 蝕。 亦可使用特殊之冷卻液體，以便替代使用水作爲冷卻 劑。然而，此僅在如果冷卻迴路本身是封閉的才可行。尤 其，這方法必須額外地設置熱交換器才能進行此冷卻劑之 冷卻。 在由鑄鐵所製之真空栗外殼中設置多個冷卻通道也 可藉由以機械製造（尤其藉由銑製及鑽製）來翻新具有此 類通道之外殻而達成。此方式將極端複雜，因其需要多個 耗時之額外加工步驟。亦可在鑄造過程中就已形成多個冷 卻通道。爲達此目的，砂心將必須被設置。此方法也是很 複雜的，且甚至冒著冷卻水可能會被殘留的砂長時間污染 之風險。另外’由砂模所成型之置入模製通道的提供將在 201042150 設計、截面與路線上受到嚴格限制，因爲此種模製成型係 藉助於在鑄造過程中必須具有充分穩定性之砂心才可進 行。因此，此類通道之提供將大大地限制了可能形狀與可 能運轉條件之範圍，而此諸運轉條件例如包含穩定性、容 許之操作溫度、及介質相容性。 在鋁鑄之真空泵外殻中，可藉由鑄入（mold-in)方式安 裝不銹鋼製之冷卻管。將不銹鋼管鑄入鋁內係可行的，因 爲在鑄鋁過程中之鑄造溫度係較小的，且鋁在冷卻階段結 〇 束時將顯著地收縮，因而可在不銹鋼冷卻管與鋁外殼之間 達成一令人滿意的緊靠面。另外，鋁具有一良好的導熱 性，以致即使不銹鋼冷卻管的外側面與鋁外殼間之相互緊 靠形成得不完整，仍可有一足夠之熱傳遞至位於冷卻管中 之冷卻介質處。然而，將冷卻管鑄入由灰鑄鐵或球墨鑄鐵 所製成之真空泵外殼元件內將不全然是很容易的，因爲在 完成灰鑄鐵或球墨鑄鐵之鑄造後，會在冷卻管與外殻元件 間產生一間隙。此空氣間隙具有一隔絕效果，並因此將對 Θ 於從灰鑄鐵或球墨鑄鐵製外殼元件傳至該冷卻管上（且因 此傳至冷卻介質上）之熱傳遞產生一負面影響。此外’一 種危險性存在於：冷卻管可能在鑄造元件中被移動或轉 動。尤其在冷卻管與冷卻導管之間的連接元件處，上述現 象之發生可能限制冷卻流動或亦可能造成損壞。另一方 面，以灰鑄鐵或球墨鑄鐵來製造真空泵外殼係非常有利 的，因爲灰鑄鐵或球墨鑄鐵之鑄造係可提供非常良好之可 塑形性的鑄造工序。 201042150 【發明內容】 本發明之一目的在於提供一種真空泵外殼，其係由灰 鑄鐵或球墨鑄鐵所製成，且其可借助於被鑄入之冷卻管而 獲得一可靠之冷卻效果。 根據本發明，上述之目的係憑藉被界定於申請專利範 圍第1項中之諸特徵而達成。 在本發明中，至少一個保持元件被設置在被模製於由 灰鑄鐵或球墨鑄鐵所製之外殼元件內之冷卻管的一外側 面上。此保持元件係用於固定此冷卻管在此外殻元件中之 位置。因此，此保持元件被設置成一延長部或伸出部之形 式或也成一位於該外側面上的凹口或壓扁部之形式，藉以 在澆鑄材料冷卻後於冷卻管與外殼元件之間建立一形狀 鎖定式（form-locking)連接。較佳地’此保持兀件被至少 部分地配置在徑向方向上。因此，冷卻管在軸向上之移位 將可被避免。另外，該至少一個保持元件或該等保持元件 中之一者被構形爲使得該冷卻管之轉動可以被避免。爲此 目的，此保持元件包括一被定向在相對於圓周方向成0° 之表面。 該至少一個保持元件不只具有可防止冷卻管在外殼 元件中移動之創新功能，且還額外地用以改良外殻元件與 被配置在冷卻管中之冷卻介質（通常是水）間的熱傳遞。藉 由外殻元件將較佳地實現一與外殼元件之表面接觸。即使 至少一個部分空氣間隙可能被產生於冷卻管與外殻元件 之間，從冷卻元件到位於冷卻管中之介質的熱傳遞仍可經 201042150 由該至少一個保持元件而被進行。在此態樣下，設置複數 個保持元件是尤其更好的。 根據一簡單之實施例，可在冷卻管之外側面上設置多 個呈焊接點形式或呈凹口或壓扁形式之保持元件，其中此 類型之保持元件當然亦可與其他之保持元件相結合。較佳 地，大量之焊接點或凹口被不規則地分布在整個外圍上並 沿著此冷卻管之全長。已經藉由特別設置複數個焊接點或 凹口，可在冷卻管與由灰鑄鐵或球墨鑄鐵所製之外殼元件 〇 間達成一形狀封閉式連接。另外，這已可改良外殼元件與 冷卻管間（且因此與在冷卻管內流動之冷卻介質間）之熱 轉移。 根據本發明之一較佳實施例，此諸保持元件被設置成 多個被配置在冷卻管之外側面上之肋件的形式。此諸肋件 可被構形爲多個單獨之腹板，其可隨意地爲銷狀或面狀腹 板。較佳地，諸肋件係環狀並環繞冷卻管，因此較佳地爲 徑向環狀肋件。或者，此諸肋件（尤其是環狀肋件）可朝向 η W 冷卻管之外側面傾斜，亦即具有一個#90°之角度。尤其當 使用此類傾斜肋件時，一與鑄造外殻元件間之形狀封閉式 連接被同樣地實現在徑向及軸向之方向上。 根據另一實施例，諸保持元件被設置成多個被固定至 冷卻管之外側面上的管件形式。此諸管件被設置成具有狹 縫。或者，此諸管件可爲只在縱長方向上形成部分管之類 型。此諸管件較佳地具有四分之一或半圓之截面。藉由對 此諸管件開設狹縫，將可確保澆鑄材料完全地進入管件之 201042150 內。依此方式，會不利地影響該熱轉移之: 被避免。 根據另一實施例’此保持元件可包括 此連接元件可使兩個或更多個冷卻管相互 管可爲不同冷卻迴路之兩條不同冷卻管， 卻迴路之多個管件。該連接元件可爲一金 該冷卻管及/或該至少一保持元件及 接元件較佳地係由鋼（尤其不銹鋼）所製。 〇 之一足夠大的壁厚，將使得冷卻管在鑄造 部分熔化可被防止。在由灰鑄鐵或球墨鑄 殼部件中，冷卻管較佳地具有2至5mm 在澆鑄程序進行期間，如果冷卻管之加熱 暖或熱空氣通過其中而從內部被予限定， 可被實現。諸保持元件及/或諸連接元件 較小壁厚，因爲部分熔化對於這些元件丨 的。 〇 w 根據本發明，諸保持元件及/或諸連 有效擴大諸冷卻管之熱傳輸表面。爲此目 件及/或此諸連接元件較佳地被形成具有 是形成爲肋件。依此方式，此熱傳輸表面 例如加倍。 諸保持元件及/或諸連接元件係以一 (較佳爲藉由焊接）而被固定至冷卻管上。 根據另一較佳實施例，該至少一冷g 空穴的產生將可 一連接元件，藉 連接。這些冷卻 或亦可爲相同冷 屬部件。 /或該至少一連 藉由選定冷卻管 期間之不合宜的 鐵所製之一般外 之壁厚。或者， 例如藉由吹冷、 則較小之壁厚亦 可選擇性地具有 而言並不是緊要 接元件較佳地可 的，此諸保持元 大的表面，尤其 可被擴大或甚至 -可導熱之方式 P管被以螺旋及/ 201042150 或旋渦形狀配置。因此，亦可在不設置保持元件下，確保 在冷卻管之外側面與外殻元件之間存在一相當大之接觸 表面。同樣地將可防止此造型之冷卻管發生移位或轉動。 冷卻管之此一造型憑其本身特徵便是一項發明，其與保持 及/或連接元件之設置無關。與上述保持及/或連接元件之 額外結合係較佳的，如此可進一步擴大熱傳輸表面。 根據另一較佳實施例，此冷卻管相對於其縱長方向係 成偏斜或彎曲。在此一實施例中，此冷卻管較佳地係成複 Θ 數次彎曲，且因此在其縱長方向上具有一蜿蜒或波狀之形 狀。以此方式被構形之冷卻管無法承受不必要之移動或轉 動，儘管灰鑄鐵或球墨鑄鐵相較於不銹鋼具有不同之冷卻 性能。另外，由於這些彎曲，使得多個相當大之緊靠表面 被實現於外殻元件與冷卻管之間。而且，此實施例憑其本 身特徵便是一項發明，其與保持及/或連接元件之設置無 關。在此，設置多個可供擴大熱傳輸表面用之保持及/或 連接元件也是較佳的。 ° 【實施方式】 諸圖式中所顯示之所有冷卻管均係一真空泵外殼之 部件，其中相同之組件在諸圖式與隨後之說明中被標示以 相同之元件符號。在所有實施例中，一個或複數個冷卻管 12被配置在一各自之泵外殼10中（示意地描繪）。 根據第一實施例（第la圖），複數個焊接點16被設置 作爲多個位於冷卻管1 2之外側面1 4上的保持元件，而此 諸焊接點以一種不規則之配置方式被分布在圓周上。 .201042150 根據另一個實施例（第lb圖），複數個凹口 17被設置 在冷卻管1 2之外側面1 4上。相當於該等焊接點1 6之設 置（第la圖），諸凹口 17之設置也可有效地防止冷卻管12 之移位或轉動。較佳地，諸凹口 1 7是很微小的，以便使 冷卻管1 2之截面積絲毫不會被改變或至少僅只極小程度 地被改變。對應於該等凹口之設置，亦可改變冷卻管12 在某些處之外部輪廓。例如，冷卻管12可在某些處被賦 予一橢圓形狀或被形成一橢圓管。 Ο 在第2圖中，冷卻管12之外側面14上配備有多個圓 形冷卻肋件1 8，其係藉由焊接而被固定至冷卻管1 2之外 側面1 4上。這些圓形冷卻肋件1 8徑向地延伸。 在第3圖中，同樣地配置有圓形之冷卻肋件20。然 而，這些肋件則是相對於冷卻管1 2之外側面1 4以一斜度 延伸。此外，諸冷卻肋件20在本實施例中係略成拱形或 弧形造型。 在第4圖中，複數個薄且較佳也是圓形之冷卻肋件 ^ 22也是藉焊接而被固定至冷卻管12之外側面14上。當 這類薄冷卻肋件被設置時，此諸冷卻肋件之一部分將高度 可能地會在澆鑄期間被熔化。 在第5圖所不之實施例中’冷卻管12再度地藉由焊 接而被固定至兩個當作保持元件之管件24上。在此’這 些管件24例如具有一圓形截面。因爲此諸管件24之長度 相當地短，所以可確保澆鑄材料將經由諸側面孔而進入此 諸管件24內。在較長管件的情形中，最好提供一縱向狹 -10- 201042150 縫2 6(第6圖）。當然，較短之管件（第5圖）也可包括—縱 向狹縫，以便確保澆鑄材料理想地快速進入。 另外，可提供呈板片金屬組件形式或經滾製之具有v 形截面之外廓件2 8形式之肋件，而該外廓件係藉由焊接 被固定至冷卻管12。 此外’兩冷卻管12可藉由一較佳具有面狀構形之連 接元件30而被相互固定。 當然，例如根據已鑄成之外殼元件內的空間，可將上 ^ 述諸不同類型之保持與連接元件相互組合。 根據另一憑其本身特徵便是一項發明的實施例（第9 圖），冷卻管12被配置在一呈彎曲形狀的外殻10中。 根據再一憑其本身特徵也是一項發明的實施例（第1〇 圖），被設置在外殼10中之冷卻管12係一具有複數個彎 曲或一波狀造型之管。 第9及10圖中所示之諸發明係憑其本身特徵便是發 0 明；然而，這些發明在其較佳實施例中被額外地連接至例 如第1至8圖中所示之保持元件。依此方式，熱傳輸表面 可被擴大。 雖然本發明已參照其多個特定實施例而被說明與圖 示，但此並非意欲將本發明限定於這些經圖式說明之實施 例。熟習本藝之人士將承認許多變化與修改可在不脫離被 界定於後附申請專利範圍中之本發明的真實範圍下被達 成。因此，本發明將涵蓋所有這些落在所附申請專利範圍 及其均等物之範圍內的變化與修改。 -11- 201042150 【圖式簡單說明】 本發明之包括其最佳模式及使熟習本藝之人±可'_ 以實施之完整且可行的揭示內容已配合參照附圖而被詳 細地提出於上文中，在此諸附圖中： 第1至7圖係具有不同保持元件之不同冷卻管實 的剖面圖； 第8圖係由一連接元件所固定之諸冷卻管的示意咅IJ 面圖； 〇 第9圖係一彎曲冷卻管之示意剖面圖；及 第10圖係一具有多道彎曲之冷卻管的示意剖面圖。 【主要元件符號說明】 10 泵外殼 12 冷卻管 14 外側面 1 6 焊接點 17 凹口 18 冷卻肋件 20 冷卻肋件 22 冷卻肋件 24 管件 26 狹縫 28 外廓件 -12 -201042150 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a vacuum chest shell made of gray cast iron or ductile iron cast iron. [Prior Art] A vacuum pump includes a plurality of pumping elements which are disposed in a pump chamber formed. The vacuum pump is mainly constructed as a Roots pump, a rotary vacuum pump, and a claw pump. In order to form a gap between the chestnut elements and the inner wall of the chestnut chamber. For this purpose, it is necessary to operate the vacuum pump at an operating temperature to avoid changes in the gap that may result from expansion of the pump casing and pump components. It is known to provide a vacuum pump having cooling ribs and to use the pump casing. However, in this case a uniform and well-oriented cooling of the outer casing will usually be achieved by special measures, such as by installing an outer casing with a good guide, or by using an external fan system (by Or driven by a separate drive unit). Other disadvantages of this air flow are: low cooling strength and difficulty in being protected from external shadows such as air currents or objects that improperly cover the pump. Further, it is conventional to carry out the vacuum pump by means of water or a cooling liquid. Water cooling requires special structural measures ® Water must be directed as close as possible to the cooling section for maximum cooling. On the other hand, water for most (spheroidal one by a shell rotary pump, Lu generated vacuum, as small as possible as uniform as possible, different thermal expansion of the airflow to cool the background technology only by some oriented air in the pump shaft The cooling effect or disturbance of the moving cooling, the cooling of the outer casing. In one side, so that the corrosion of the material can be divided into 201042150 erosive effect will make it impossible to use water without special protection measures. In order to avoid corrosion, it can be used without corrosion. Materials such as non-mirror steel or specific aluminum alloys. However, such materials are expensive and do not meet other prerequisites for vacuum pump housings, such as high temperature resistance, especially greater than 250 ° C. Alternatively, they can also be in contact with water. Painting the surfaces of the paint. It is very complicated to paint a plurality of corresponding passages at the inner side of the outer casing. This painting procedure must be carried out by immersing the bath or by agitating and turning the paint. In addition, electroplating surface treatment methods (such as galvanizing or nickel plating) are conventionally used in the case of cast steel and gray cast iron, while hard anodes The rule is conventionally used in the case of aluminum. However, these methods are also very complicated. In addition, another conventional method is to use a consumable electrode, but it is also a complicated method and cannot be used in the case of an internal cooling channel. Corrosion is reliably prevented. Special cooling liquids can also be used instead of using water as a coolant. However, this is only possible if the cooling circuit itself is closed. In particular, this method requires an additional heat exchanger to carry out this. Cooling of the coolant. The provision of a plurality of cooling channels in a vacuum pump housing made of cast iron can also be achieved by mechanically manufacturing, in particular by milling and drilling, to retrofit an outer casing having such a passage. The approach will be extremely complex, as it requires multiple time-consuming additional processing steps. Multiple cooling channels can also be formed during the casting process. For this purpose, the sand core will have to be set. This method is also very complicated. And even risking the cooling water may be contaminated by residual sand for a long time. In addition, the provision of the molded channel formed by the sand mold will be set at 201042150. The gauges, sections and routes are severely limited, since such moulding can only be carried out by means of a sand core which must have sufficient stability during the casting process. Therefore, the provision of such passages will greatly limit the possible shapes. And the range of possible operating conditions, for example, including stability, allowable operating temperature, and media compatibility. In aluminum cast vacuum pump housings, stainless steel can be mounted by mold-in The cooling tube made of stainless steel tube is feasible because the casting temperature in the process of casting aluminum is small, and the aluminum will shrink significantly when it is bundled in the cooling stage, so it can be used in the stainless steel cooling tube. A satisfactory abutment surface is achieved between the aluminum casing and the aluminum casing. In addition, the aluminum has a good thermal conductivity, so that even if the outer side of the stainless steel cooling pipe and the aluminum casing are in close contact with each other, there is still enough The heat is transferred to the cooling medium located in the cooling tube. However, it is not entirely easy to cast a cooling tube into a vacuum pump housing element made of gray cast iron or ductile iron because after casting the gray cast iron or ductile iron, it will be between the cooling tube and the outer casing element. Create a gap. This air gap has an insulating effect and thus has a negative effect on the heat transfer from the gray cast iron or ductile iron outer casing element to the cooling pipe (and thus to the cooling medium). Furthermore, a hazard exists in that the cooling tube may be moved or rotated in the casting element. Especially at the connection elements between the cooling tube and the cooling duct, the occurrence of such phenomena may limit the cooling flow or may cause damage. On the other hand, it is advantageous to manufacture a vacuum pump casing from gray cast iron or ductile iron because the casting of gray cast iron or ductile iron provides a very good formability casting process. SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum pump casing which is made of gray cast iron or ductile iron and which can obtain a reliable cooling effect by means of a cast pipe to be cast. In accordance with the present invention, the above objects are achieved by virtue of the features defined in item 1 of the scope of the patent application. In the present invention, at least one of the retaining members is disposed on an outer side surface of the cooling tube molded into the outer casing member made of gray cast iron or ductile iron. This retaining element is used to secure the position of the cooling tube in this housing element. Thus, the retaining element is provided in the form of an extension or extension or also in the form of a recess or flattened portion on the outer side surface, whereby a cooling element is formed between the cooling tube and the outer casing element after the casting material has cooled. Form-locking connection. Preferably, the retaining member is at least partially disposed in the radial direction. Therefore, the displacement of the cooling tube in the axial direction can be avoided. Additionally, one of the at least one retaining element or the retaining elements is configured such that rotation of the cooling tube can be avoided. For this purpose, the retaining element comprises a surface that is oriented at 0° with respect to the circumferential direction. The at least one retaining element not only has an innovative function of preventing movement of the cooling tube in the outer casing element, but is additionally used to improve heat transfer between the outer casing element and a cooling medium (typically water) disposed in the cooling tube. Preferably, a housing element is brought into contact with the surface of the housing element. Even though at least a portion of the air gap may be created between the cooling tube and the outer casing element, heat transfer from the cooling element to the medium located in the cooling tube may be performed by the at least one retaining element via 201042150. In this case, it is especially preferable to provide a plurality of holding elements. According to a simple embodiment, a plurality of retaining elements in the form of solder joints or in the form of recesses or squash can be provided on the outer side of the cooling tube, wherein the retaining element of this type can of course also be combined with other retaining elements. . Preferably, a plurality of weld points or recesses are irregularly distributed throughout the periphery and along the entire length of the cooling tube. A shape-closed connection between the cooling tube and the outer casing element made of gray cast iron or ductile iron has been achieved by means of a plurality of weld points or recesses. In addition, this has improved the heat transfer between the outer casing element and the cooling pipe (and therefore between the cooling medium flowing within the cooling pipe). According to a preferred embodiment of the invention, the retaining elements are provided in the form of a plurality of ribs arranged on the outer side of the cooling tube. The ribs can be configured as a plurality of individual webs that can optionally be pin-shaped or planar webs. Preferably, the rib members are annular and surround the cooling tube and are therefore preferably radial annular rib members. Alternatively, the ribs (especially the annular ribs) may be inclined towards the outside of the η W cooling tube, i.e. having an angle of #90°. Especially when such inclined ribs are used, a form-closed connection to the cast housing element is likewise achieved in the radial and axial directions. According to another embodiment, the retaining elements are provided in the form of a plurality of tubular members that are secured to the outer sides of the cooling tubes. The tubes are arranged to have a slit. Alternatively, the tubes may be of a type that only forms a partial tube in the longitudinal direction. The tubes preferably have a quarter or semi-circular cross section. By slitting the tubes, it is ensured that the casting material completely enters the tube's 201042150. In this way, the heat transfer can be adversely affected: it is avoided. According to another embodiment, the retaining element can comprise such a connecting element that allows two or more cooling tubes to be mutually piped into two different cooling tubes of different cooling circuits, but a plurality of tubes of the circuit. The connecting element may be a gold. The cooling tube and/or the at least one retaining element and the connecting element are preferably made of steel, especially stainless steel. One of the wall thicknesses large enough to allow the cooling tube to melt in the cast portion can be prevented. In the case of a gray cast iron or a spheroidal molded shell member, the cooling pipe preferably has a thickness of 2 to 5 mm, which can be realized if the heating of the cooling pipe or the passage of hot air therein is internally defined during the casting process. The retaining elements and/or the connecting elements are of a smaller wall thickness because the partial melting is for these elements. According to the invention, the retaining elements and/or connections effectively expand the heat transfer surfaces of the cooling tubes. For this purpose and/or the connecting elements are preferably formed with a rib. In this way, the heat transfer surface is for example doubled. The retaining members and/or the connecting members are secured to the cooling tube by a (preferably by welding). According to a further preferred embodiment, the generation of the at least one cold g cavity will be connectable by a connecting element. These coolings may also be the same cold components. / or at least one of the general outer wall thicknesses made by the unsuitable iron during the selection of the cooling tube. Alternatively, for example, by blowing cold, a smaller wall thickness can also optionally have a surface that is not critical, and the surfaces of the retaining elements can be expanded or even thermally conductive. The P tube is configured in a spiral and / 201042150 or a vortex shape. Therefore, it is also possible to ensure that there is a relatively large contact surface between the outer side of the cooling tube and the outer casing element without providing the retaining element. Similarly, the cooling tube that prevents this shape is displaced or rotated. This shape of the cooling tube is by itself an invention which is independent of the arrangement of the holding and/or connecting elements. An additional combination with the above-described holding and/or connecting elements is preferred, which further expands the heat transfer surface. According to another preferred embodiment, the cooling tube is skewed or curved relative to its longitudinal direction. In this embodiment, the cooling tube is preferably embossed several times and thus has a meandering or wavy shape in its longitudinal direction. Cooling tubes that are configured in this manner cannot withstand unnecessary movement or rotation, although gray cast iron or ductile iron have different cooling properties than stainless steel. In addition, due to these bends, a plurality of relatively large abutment surfaces are achieved between the outer casing element and the cooling tube. Moreover, this embodiment is an invention by its own nature, which is independent of the arrangement of the holding and/or connecting elements. Here, it is also preferred to provide a plurality of holding and/or connecting members for enlarging the heat transfer surface. [Embodiment] All of the cooling tubes shown in the drawings are part of a vacuum pump casing, and the same components are denoted by the same reference numerals in the drawings and the following description. In all embodiments, one or more of the cooling tubes 12 are disposed in a respective pump housing 10 (schematically depicted). According to a first embodiment (Fig. 1a), a plurality of solder joints 16 are provided as a plurality of retaining elements on the outer side 14 of the cooling tube 12, and the solder joints are distributed in an irregular arrangement. On the circumference. .201042150 According to another embodiment (Fig. lb), a plurality of notches 17 are provided on the outer side 14 of the cooling tube 12. Corresponding to the arrangement of the solder joints 16 (Fig. 1a), the arrangement of the recesses 17 can also effectively prevent the displacement or rotation of the cooling tubes 12. Preferably, the notches 17 are very small so that the cross-sectional area of the cooling tube 12 is not changed at all or at least only to a very small extent. Corresponding to the arrangement of the notches, the outer contour of the cooling tube 12 may also be changed. For example, the cooling tube 12 may be given an elliptical shape or formed into an elliptical tube at some point.第 In Fig. 2, the outer side 14 of the cooling pipe 12 is provided with a plurality of circular cooling ribs 18 which are fixed to the outer side 14 of the cooling pipe 1 2 by welding. These circular cooling ribs 18 extend radially. In Fig. 3, a circular cooling rib 20 is similarly arranged. However, the ribs extend at a slope relative to the outer side 14 of the cooling tube 12. Further, the cooling ribs 20 are slightly arched or curved in this embodiment. In Fig. 4, a plurality of thin, and preferably circular, cooling rib members 22 are also secured to the outer side 14 of the cooling tube 12 by welding. When such thin cooling ribs are provided, one of the cooling ribs will be highly likely to be melted during casting. In the embodiment of Fig. 5, the cooling tube 12 is again fixed to the two tubular members 24 as holding members by welding. Here, these tubular members 24 have, for example, a circular cross section. Because the length of the tubular members 24 is relatively short, it is ensured that the casting material will enter the tubular members 24 via the side holes. In the case of longer tubulars, it is preferred to provide a longitudinal narrow -10- 201042150 slit 26 (Fig. 6). Of course, the shorter tube (Fig. 5) may also include a longitudinal slit to ensure ideal entry of the casting material quickly. Alternatively, a rib member in the form of a sheet metal component or a rolled v-shaped cross-section member 28 may be provided, and the outer member is fixed to the cooling tube 12 by welding. Further, the two cooling tubes 12 can be fixed to each other by a connecting member 30 which preferably has a planar configuration. Of course, the different types of holding and connecting elements described above can be combined with each other, for example, depending on the space within the cast outer casing element. According to another embodiment of the invention (Fig. 9), the cooling tube 12 is disposed in a housing 10 having a curved shape. According to still another embodiment of the invention (Fig. 1), the cooling tube 12 disposed in the outer casing 10 is a tube having a plurality of curved or corrugated shapes. The inventions shown in Figures 9 and 10 are characterized by their own characteristics; however, these inventions are additionally coupled in their preferred embodiments to retention elements such as those shown in Figures 1-8. . In this way, the heat transfer surface can be enlarged. While the invention has been illustrated and described with reference to the particular embodiments embodiments Those skilled in the art will recognize that many variations and modifications can be made without departing from the true scope of the invention as defined by the appended claims. Therefore, the present invention is intended to cover all such modifications and alternatives -11- 201042150 [Brief Description of the Drawings] The complete and feasible disclosure of the present invention including its best mode and the person skilled in the art can be implemented in detail with reference to the accompanying drawings. Herein, in the drawings: Figures 1 through 7 are cross-sectional views of different cooling tubes having different holding elements; Figure 8 is a schematic 咅IJ view of the cooling tubes fixed by a connecting member; Figure 9 is a schematic cross-sectional view of a curved cooling tube; and Figure 10 is a schematic cross-sectional view of a cooling tube having multiple bends. [Main component symbol description] 10 Pump housing 12 Cooling tube 14 Outer side 1 6 Soldering point 17 Notch 18 Cooling rib 20 Cooling rib 22 Cooling rib 24 Pipe fitting 26 Slit 28 External member -12 -